Method of and mechanism for forming hardened steel



R. C. ANGELL March 3, 1936'.

METHOD OF AND MECHANISM FOR FORMING HARDENED STEEL Original Filed Oct. 5, 1931 ll Sheets-Sheet l vMarch 3, 1936. R. c. ANGELL METHOD OF AND MECHANISM FOR FDRMING HARDENED STEEL Original Filed 001:. 5', 1931 ll Sheets-Sheet 2 FIGI. 240 Q m 16 0 B 53521 1 D 37 3 5 61 0 60a '6 o .o a l 62 25 01 5.5

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METHOD OF AND MECHANISM FOR FORMING HARDENED STEEL Original Filed Oct. 5, 1931 ll Sheets-Sheet 3 SENRN R. C. ANGELL March 3, 1936.

METHOD OF AND MECHANISM FOR FORMiNG HARDENED STEEL Original Fi led Oct. 5, 1951 ll Sheets-Sheet 4 FIG.- 1K

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METHOD OF AND MECHANISM FOR FORMING HARDENED STEEL Original Filed 001;. 5, 1951 11. Sheets-Sheet e vwentoo R. c. ANGELL 2,032,901

METHOD OF AND MECHANISM FOR FORMING HAIRDENED STEEL March 3, 1936.

Original Filed Oct'. 5, 1931 ll Sheets-Shetf'? March 3, 1936. R. c. ANGELL 2,032,901

METHOD OF AND MECHANISM FOR FORMING HARDENED STEEL Original Filed Oct. 5, 1931 11 Sheefcs-Sheet 8 R. C. ANGELL March 3, 1936.

Original Filed Oct. 5, 1951 ll Sheets-Sheet 9 M QWN QQN ' attoznu um/M01;

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R. C. ANGELL Original Filed Oct. 5, 1931 METHOD OF AND MECHANISM FOR FORMING HARDENED STEEL I attowuug March 3,1936. R. c. ANGELL 2,032,901

METHOD OF AND MECHANISM FOR FORMiNG HARDENED STEEL Origix ml Filed Oc t. 5, 1951 ll Sheets-Sheet ll amount Patented Mar. 3, 1936 UNITED STATES PATENT OFFICE DIETHOD OF AND MECHANISM FOR- FORMING HARDENED STEEL Original application October 5, 1931, Serial No. 567,059. Divided and this application February 5, 1934, Serial No. 709,755

. 14 Claims.

This invention relates particularly to that class of devices that are adapted to forming articles of manufacture by abrading blanks to form the article into the desired shape or form and is a division of my prior application Serial No. 567,- 059, filed October 5, 1931, issued February 6, 1934, Patent No. 1,945,510.

In the forming of edges on hardened steel difficulty has always been experienced by reason of the tendency of the operation if performed with sufficient rapidity to draw the temper of the steel. Resort has therefore frequently been had to the preliminary formation of the edge upon the steel before hardening, followed by a hardening operation and a subsequent perfectingof the edge after hardening. According to my invention I have succeeded in accomplishing the entire formation of the edge on steel which has been hardened in one operation, and this I have further accomplished with great rapidity and without the generation of such temperature as will injure the temper of the steel, and further, the formation requires such small forces that delicate articles may be shaped to the desired form without distortion due to their flexibility during the shapin operation. By way of example my invention finds utility in the manufacture from hardened steel blanks of burs such as are used in the dental art, and I will illustrate my invention by reference to this manufacture, although its application is far wider.

Such a bur has a properly shaped head of hardened steel which must be furnished with a subcession of sharp cutting edges, and the difllculties to which I have referred have been acutely experienced in the manufacture ofthesev articles until my present invention has succeeded in overcoming them. Previous to my invention these articles were customarily produced and shaped in steel which had not been hardened, and after the cutting of the teeth the steel was hardened and then subjected to a finishing operation to perfect the desired cutting edge. This procedure is troublesome and expensive. By my operation this trouble and expense is avoided since the entire production of the head and of its sharp ened edge is accomplished after the hardening of the steel and without injuriously aflecting the quality and temper of the steel.

While I have spoken of my invention as applicable to operations for the production of hardened steel edges yet it is obvious that the same shapes in hardened steel has usually been accomplished by a grinding operation, that is to say, an operation in which the roughened surface of a grinding wheel accomplishes the shaping of the metal. The grinding is accomplished by abrasive particles permanently incorporated within or temporarily embedded within (as in lapping) the grinding surface.

It is characteristic of my invention that the steel surface is operated upon not by abrasive particles incorporated within the wheel but by abrasive particles carried by a fluid, such as an oil of proper consistency, which is injected between the rotating surface of a very hard wheel and the steel surface to be acted upon. This I have accomplished by the use of a wheel of much greater hardness than (so far as I can ascertain) has ever been used in similar operations. 80 hard is the surface of this wheel that it does not receive or hold the abrasive particles which flow over its surface. It merely temporarily propels them.

My invention involves a new process or method or procedure in the forming of hardened steel and I will first describe this new process and subsequently describe mechanism which is well adapted for the practice of my process. Grinding wheels are,made by embedding very finely divided particles of abrasive in a bond or matrix. The abrasive particles may be emery or carborundum or alundum or similar particles. The matrix or bond is necessarily less hard than the abrasive but must be capable of effecting firm incorporation of the abrasive. If the matrix is too hard the grinding operation will not be properly performed because successful grinding is dependent upon continuous disintegration of the grinding surface whereby new abrasive particles are brought into action and the necessary irregularity of the grinding surface thus perpetuated. If the bond be too hard the projecting abrasive surfaces are worn down and the grinding surface becomes glazed. It therefore ceases to disintegrate and loses its grinding power. must always be tenacious enough to firmly incorporate the abrasive yet, on the other hand, sufficiently soft to be gradually worn away, thus increasing the projecting of each of the abrasive particles to the point where the particle is released with formation of a new roughened surface on the wheel.

According to my present process I employ a wheel having a matrix or vitrified bond which is the hardest commercially available. Some manufacturers of wheels designate this as grade Z,

Therefore the matrix ute) and in close proximity to the hardened steel surface to be formed I inject a stream of rather viscous oil such, for example, as sperm-oil, carrying with it a high proportion of a suitable abrasivesuch as fine emery. The proportion of oil to abrasive may be about one pint of oil to a pound of emery. This mixture is freely supplied by injection. As the grinding surface approaches the hardened steel surface to be formed the projections or roughenings of the grinding surface occasion a propulsion and some temporary adhesion of the floating abrasive acting somewhat according to the analogy of the vanes of a centrifugal pump- It is therefore the floating abrasive andnot the abrasive incorporated within the wheel which accomplishes the major formative action upon the steel. From this distinction important advantages flow, for even though the rotating wheel be forcibly advanced with rapidity toward the surface to be formed it is not unduly involved inthe operation since the major work of removing Particles of steel falls upon the floating abrasive, Furthermore, each abrasive particle when it has accomplished its work upon the steel surface (with attendant generation of some heat) is immediately removed from the operation so that there is no cumulative heating effect such as is experienced in the grinding of hardened steel due to the heating up of the grinding edges as they repeatedly come into operative position.

My process is the more efficient as the size of the floating abrasive particles is reduced within practical limits, for the increase in the number of the abrasive particles distributes the work and the resultant heating up of the particles and lessens the tendency to any objectionable heating of the metal surface acted upon. These fine abrasive particles float in the oil with production of an emulsion, in which form the supply and distribution of abrasive is capable of accurate and complete control.

I have also found that it is desirable that the floating abrasive while necessarily harder than the steel surface which is to be formed, should not be harder than but preferably softer than the abrasive particles incorporated in or embedded within the wheel. This lengthens the life to! the wheel becauseas between the abrasive incorporated in the wheel and the floating abrasive, if the former is harder it is the latter which breaks or yields if breaking forces are created between the two.

A valuable fleld for the employment of my invention is, as I have stated, the formation of dental burs. In this art a steel rod is cut into suitable blanks and upon each blank after hardening a suitable shaped head is formed and thereafter suitable teeth are cut in the head. I will describe two pieces of mechanism adapted to successively form the head and then cut the teeth therein, in bothof which operations. I utilize my process.

Referring to the drawings, Fig. I shows a plan view of a machine embodying my invention for forming the head of the bur.

Fig. II is a side elevation of the machine with portions thereof broken out and sectioned to illustrate important parts which would otherwise be hidden.

Fig. III is a staggered sectional view of the machine taken as indicated by the arrows IIIIII in Fig. I.

Fig. IV is a fragmentary view of the left hand end of the machine, drawn to a larger scale and having portions in section in the plane of the arrows IV-IV in Figs. I, II and V.

Fig. V is a fragmentary longitudinal sectional view also drawn to a larger scale, and taken as indicated by the arrows V-V in Fig. I, showing the means whereby the blanks are fed and the means whereby the said blanks are held and rotated incident to shaping.

Fig. VI is a fragmentary detail view showing the means for discharging the abrasive fluid at high velocity onto a blank in position between the backing wheels of the machine.

Figs. VII and VIII are fragmentary sectional views taken as indicated respectively by the arrows VIIVII and VIII-VIII in Fig. VI.

Fig. IX shows a perspective view of the abrasive fluid discharging nozzle; and

Fig. X is a fragmentary detail view showing how the blank .is profiled by the backing disks of the machine.

Another machine embodying my invention for cutting the teeth on the head of the bur is illustrated in Figs. XI to XX of the drawings, whereof Fig. XI shows a side elevation of this toothcutting machine.

Fig. XII is a plan view of tooth-cutting machine drawn to a somewhat larger scale.

Fig. XIII is a longitudinal sectional view taken as indicated by the arrows XIII-XIII in Fig. XII.

Figs. XIV and XV are cross sectional views of' he tooth-cutting machine taken as indica d respectively by the arrows XIVXIV and XV in Figs. XI, XII and XIII. Fig.- XVI is a. diagrammatic illustration partly in side elevation and partly in section, drawn to.

the machine of Figs. I--X; and

Fig. XX is a perspective view of the finished. dental bur with the cut teeth.

The machine shown in these illustrations, comprises a hollow pedestal-like base ll having a T-shaped top or platen H, on which is mounted a hollow rectangular frame l3, that affords bearings Ba and l3b for a .tubular horizontal work holding spindle l5, see Fig. V. Keyed to the spindle I5 is a cone pulley I 6 which is adapted to be driven at selectable speeds, by a belt I! from a similar pulley (not shown) on a drive shaft within the hollow base H;the projecting end of the said drive shaft being indicated at i8 in Figs. I and II. The tubular spindle I5 is provided with a chuck sleeve l9, which surrounds a split jaw chuck 20, and which is retained by an inwardly-flanged cap 2| secured over the adjacent end of the spindle.

From Fig. V it will be noted that a chuck rod 22 lodged in the spindle I with the chuck sleeve I9 has an axial bore 23 into which the bur blanks B are successively introduced at the right hand end, from a columnar-supply magazine 24, the

latter being supported by a horizontal arm 25- aflixed to a lateral bracket 26 at one end of the machine frame The bur blanks B are stacked one above another, within the magazine 24, which, as shown in Figs. II, IV and V, is open at one side, and has its solid wall cut away at the top as at 21 to afford clearances for the fingers incident to charging the magazine with the blanks. The chuck 20 is radially contracted as a consequence of wedge action between its coned surface 28 and the correspondingly tapered internal surface 29 of the chuck sleeve I9.

In line with the spindle I5 and underlying the magazine 24 is a fixed bar 36 which reaches forwardly from a boss 3| of the extension bracket 25, the said bar having a longitudinal groove 32 in its top adapted to successively receive the lowermost blanks of the stack in the magazine 24. Slidably guided on the bar is a carriage 33 comprising an underbody 34 and a screw attached top plate 34a, which latter overlies the said bar. Extending longitudinally through one side of the underbody 34 of the carriage 33 and having projection beyond both ends of the latter is a rod 35; and surrounding the outer end of this rod is a coiled spring 36 which is in compression be tween the carriage 33 and a collar 31 pinned to the rod. At its inner end, the rod carries a pair of collars 38, 39 between which engages a lateral finger 46 of a head 4| with guidance for horizontal recipro'catory movement on a way 42 forming a part of the bracket 26, see Figs. I and V.

The slide head 4| is moved along its guide way 42 by a roller arm 43 which is fulcrumed to swing on a fixed pivot 44 and actuated by a drum cam 45 alongside another drum cam 46 on a shaft 41, the movement so imparted to the head being somewhat in excess of the length of the bur blanks. As shown in Fig. V, the connecting center 48 between the carriage 4| and its actuating roller arm 43 is adjustable by means of a screw bolt 49 lodged in an angularly disposed lateral ofiset 50 of the said carriage. By this means, the throw of the carriage can obviously be adjusted to properly feed blanks of differentlengths. In this connecton the function of spring 36 is to permit the carriage to yield when the bur being fed through the chuck 26 reaches the position determined by the stop 60 subsequently described, thereby pressing the end of the bur against the stop with a definite pressure prior to closing of the chuck 20.

After shaping of a blank B, the chuck 20 is automatically released through retraction of the sleeve I9 by a coiled spring 5| in compression between the inner end of the said chuck and an internal circumferential shoulder of the said sleeve. Such release of the chuck is effected through axial shifting of the rod 22 by a series of radially arranged fingers 52 having pivotal support in slots in that end of the spindle which projects beyond the bearing I3a, and adapted to be rocked on their pivots by a collar 53 which is slidable on the projecting portion of the spindle 85 depending respectively-from their shafts 86 I5. The collar 53 is in turn actuated by a lever 54 which is fulcru'med in a bracket 55 reaching laterally from the bearing member I3, and which is actuated by the rotary drum cam 46 on a shaft 41, see Figs. IV and V.

Concurrently with release of the chuck and with introduction of a new bur blank B from the magazine 24 into the outer end of the spindle I5 through forward movement of the feed carriage 4| in the manner previously explained. a shaped bur B is ejected from the opposite end of the spindle I5; while the succeeding bur blank B is intercepted by a stop 60 which is aligned with the said spindle and which is at this time moved forward from a normal retracted position through shifting of a slide 6| which supports it. see Figs. I and II. This slide BI is confined to a horizontal guide-way in the top |2 of the machine base and said slide has secured to it at the bottom, a toothed rack 62 wherewith meshes a segmental gear 63 having pivotal support at 64 on a fixed bracket 65 withinthe hollow of the machine base II, see Fig. II. The segmental gear 63 is rocked on its pivot 64 through cooperation of a roller 66 thereon with a rotary cam 61 on a transverse shaft 68, also within the machine base II, the said shaft being driven in synchronism with the shaft 41 which carries the drum earns 45 and 46. A spring 69 influential upon the slide 6| for the stop 68, serves to maintain the roller 66 on the segmental gear 63 always in yielding contact with the rotary cam 61. At 60a is shown a means whereby the stop 60 may be adjusted longitudinallyin its supporting slide 6| to adapt the machine for operation upon bur blanks of different lengths. The function of the stop 66 is to accurately determine the extent of projection of the individual bur blanks B beyond the end of the chuck 20 for presentation between a pair of backing wheels and H.

The shaft 41 is driven in unison with shaft 68 having suitable connections (not shown) within the base II and is actuated by a toothed clutch tripped by a dog attached to a drum on shaft 88. This construction is not shown since it is one well known in the art of automatic screw machines being used in these machines for the feeding cycle.

These backing wheels 10 and 1| are exactly alike, and, in accordance with my invention, are made to disk form. They are composed of particles of abrasive, such as alundum, in a bond or matrix vitrified to an excessively hard consistency harder than suitable for grinding purlposes for reasons already explained. Their peripheries are curved as at 10a, 1|a respectively, and shouldered circumferentially as at 181), Nb, to determine the profile of the cut made laterally into the side of the bur blank B, see Fig. X. The spindles 12 and 13 of the backing wheels 10 and 1| are journalled in separate bearings 14, 15 upstanding from slides 16 and 11 with guidance on the lateral wings I lb, ||c of the machine base II, for movement toward and away from the axis of the chuck 20. .The described movements are simultaneously imparted'to the bearing slides 16, 11 of the backing wheels .16, 1| during the shaping of each bur blank B, by means of segmental gears 18, 19, which are secured to separate'shafts 80, 8| journalled in the ma chine base top I2 as shown in Fig. HI, and which mesh with rack bars 82 and 83 within bottom hollows of the said bearing slides.

The segmental gears 18 and 19 are rocked as a consequence of the actuation of roller arms 84,

and 8|, by rotary cams 86 and 81 on a pair of shafts 88, 89 which are rotative in bearings 90,

9| affixed to opposite sides of the machine base II. Springs 92, 93 lodged in lateral cavities 94, 95 in the machine base top I2 tend to move the slides 16 and 11 outward and thereby maintain the rollers on the arms 84 and 85 in yielding contact with the rotary cams 86 and 81. In order that the limit of inward movement of the backing wheels 10 and 1 I may be varied to determine the desired depth of the lateral cut made in the bur blanks B, the slides 16 and 11 are adjustable relative to the gear racks 82 and 83. The means whereby these adjustments are made include threaded sleeves 96, 91 (Fig. III) which engage tapped apertures in the opposite ends of the slides 16 and 11, the said sleeves bearing at their inner ends against the ends of the rack bars 82 and 83 and. being axially bored for passage of headed rod extensions 98 and 99 of the said rack bars. At their outer ends the threaded sleeves 96 and 91 are provided with hand wheels I00, IOI for convenience of making the adjustments. Obviously, as the sleeves 96, 91 are rotated in one direction or the other, the slides 16 and 11 are shifted correspondingly with relation to the toothed racks 82 and 83, for the purpose aforesaid. After the adjustments are made, the sleeves 96 and 91 are secured against accidental displacement by means of jamb nuts shown at I02, I03. The backing wheels 10 and II are driven at a high rate of speed in the direction of the arrows shown in Figs. III and VI as a consequence of the coordination of pulleys I04 and I05 on their spindles 12 and 13 with larger pulleys I06, I01 on the main drive shaft I8 of the machine, by means of belts I08, I09, see Figs. I and II.

The abrasive fluidwhich is relied upon to effect the actual cutting of the bur blanks is discharged downwardly through a nozzle IIO allocated within the tapered or wedge-shaped pass between the two backing wheels 10, H, and onto the sides of the bur blank B which is being cut, see Figs. III, VI, VII, VIII and IX.. The abrasive fluid is preferably a mixture of sperm-oil and finely comminuted emery. It is continuously and freely supplied to the nozzle IIO, through a pipe line I I I, from a reservoir I I2 shown in Fig. III as being bolted to a bracket I I3 at one side of the machine base II. As shown, the pipe II I connects at its bottom end with a centrifugal pump II4, which is driven by means of a belt II5 from a suitable source of power (not shown) and which draws the liquid abrasive from within the reservoir II2. Interposed in the pipe II I is a hand valve II6 for controlling the rate of flow of the abrasive fluid from the nozzle H0. The discharge from the nozzle, after impinging upon the backing wheels 10 and" is directed, through an opening H1 in the top I2 of-the machine base I I into a vertical conduit II8 with an inclined bottom portion II9 which discharges, in turn, through a terminal spout I20 into a counter-inclined trough I2I whereby the fluid is returned to the reservoir II2, all as shown in Fig. Disposed within the inclined portion II9 of the conduit H8 is a perforated plate I22 which permits passage of the abrasive fluid but intercepts the shaped burs B as they are ejected from the chuck 20 to fall down through the opening H1 and the conduit II8,

. and diverts the said shaped burs into a receiving tray I23 set apart in the trough I2I by a transverse partition I24. 1

Referring again to Figs. VI-IX it willbe observed that the tapered end of the nozzle II 0 is flattened to rectangular form as at I 25and subdivided by a central partition I26 with resultant formation of two separate elongate outlets. As shown, the partition I26 is extended beyond the end of the nozzle IIO into close proximity to the bur blank B undergoing cutting. It will also be noted that the partition I26 is gouged out at opposite sides of its lower end as at I21, I 28 so that the two streams discharged from the nozzles are accurately directed between the peripheries of the backing wheels 10 and H and the opposite sides of the bur B at the regions where the metal of the bur is being cut away. Lateral spread of the stream of abrasive at the nozzle H0 is confined between a pair of guard plates I29, I30 which overlap the backing wheels 10 and H as well as the nozzle end. As shown, the guard plate I30 is formed with a vertical slit I3 I which will permit the shaped blanks to drop freely when ejected by the chuck 20; while the companion guard plate I29 has an opening I32 for the bur blanks,

see Figs. VII and VIII. To prevent entry of the abrasive fluid into the bur-blank-holding end of the spindle I5, another.

fluid, such as lubricating oil, is forced out from within the said spindle through the chuck 20 under pressure. 'This protective fluid is introduced from a suitable source of supply (not By action of the rotary cams 86, 81, the backing wheels 10 and II are first rapidly advanced si-' multaneously into position proximate the rapidly revolving blank B held in the chuck, and from then on, urged inward at a slower rate thereby insuring a gradual and even cut into the blank from opposite sides. As a consequence of such cutting, the blank bur is formed with a headH,

\ see Fig. X.

As illustrated in Figs. XI-JDL the tooth-cutting machine is supported at an inclination to the horizontal, by a substructure 2I0, which, in the present instance, is constructed from timber, with a solid top 2I I whereto the frame parts of the machine are rigidly secured. These frame parts include a pair of transversely-disposed end brackets 2I2 and 2I3 which afford laterallyspaced guide-ways 2H and 2I5'for the longitudinally-extending slide bars 2I6 and 2 of a work supporting carriage 2I8. The bars 2I6 and 2", are connected at opposite ends by cross members 2I9 and 220, as shown in Figs. XI, XII and XIII. Rollers 22I and 222 with journal support respectively in bridging blocks 223 and 22lbolted to the end brackets 2I2 and 2I3 over the guideways 2 and 2I5, bear on the slide rods 2I6 and 2", and thus serve to hold the carriage 2I8 against upward displacement. Reciprocatory movement is imparted to the carriage 2| 8 as a consequence of cooperation of a roller 225 at the depressed end thereof, with a rotary cam 226 on one end of a transverse shaft 221 which rotates in a'bearing' bracket 228 bolted to the top 2I I 01' the substructure 2 I0 at the corresponding end of the machine. The roller 225 is maintained in contact with the cam 226 solely through influence of gravity upon the carriage 2 I8. The shaft 221 receives motion, through the medium of a ,worm gear couple 229, from a shaft 230 at right angles, whereon is secured a pulley 231 for beltcoordination with a suitable source of power, not

illustrated. p

Extending crosswise between the side bars 2I6 and III of the carriage 2 I8 intermediate the ends said yoke in adjusted positions.

. B on which teeth are to be cut.

of the latter, is a bridging member 232 having an upward central arching portion with a semicircular opening 234 therethrough. Pivotally connected at 235 to opposite sides of the bridging member 232, with capacity for angular adjustment, is a yoke 236; and at 231 and 238 is shown a pair of opposing set screws for-securing the Fulcrumed in turn on the yoke 236 at 239, is a cradle 248; and rotatable in a central horizontal boss 2 of the said cradle is a chuck sle'eve 242 which projects forwardly through the opening 234 of the bridging member 232 and is adapted to.receive thebur As the carriage 2l8 reciprocates horizontally under the influ ence of the rotary cam 226, the head H of the bur blank B is presented tangentially to a profiling or backing wheel 245, which latter has the form of a circular disk with a beveled periphery 246 to determine cutting of teeth of the form shown at T in Fig. XX into the head H of the bur.

Concurrently with horizontal reciprocation of the carriage 2l8, the cradle 248 is rocked on its fulcrum connections 239 with the yoke 236, so that the head H of the bur blank is moved radially toward the center of the backing wheel 245 until a cut of the desired depth is made, and

thereupon again withdrawn from the said wheel with attendant easement of the cutting. Such rocking movement of the cradle is induced through action of another rotary cam 241 on the shaft 221, upon a forwardly reaching arm 248 secured to the cradle at one side, see Figs. XI and XII, the said arm being maintained in contact with the cam by means of a compression spring 249 shown in Fig. XI. Obviously, the depth of the cut made in the bur head can be varied by angularly adjusting the yoke 236 to which the cradle 248 is pivoted, with the aid of the set screws 231 and 238 aforementioned. During cutting, the end of the bur B is held against flexing downwardly by a notched rest plate 248 at the forward end of the cradle 248, see Fig. XIII.

As shown in Fig. XIII, the bracket piece 258, carrying the roller 225 is adjustable relative to the cross member 2 l3 of the carriage 2 l 8 by means of. a set screw 25l, and securable in adjusted positions by a clamp bolt 252 which passes through an elongate slot 253 in the said bracket piece and takes into the cross member. The means just described makes it possible to suit the range of the reciprocatory movement of the carriage 218 to the backing wheel 245 in accordance with the length of the head of the bur B which is being cut in the machine.

Referring to Figs. XI, XII, XIII, the backing wheel 245 is secured to a spindle 255 which is rotatively journalled in a bearing 256 at one end of a supporting plate 251. At its opposite end this supporting plate251 is pivoted, by means of needle point screws 258, to an upward bracket 259 bolted to the top 2 of the substructure 2i8. Through the medium of the thumb screw 268 engaged in an extension 26! of the free end ofthe supporting plate 251 and bearing against a fixed abutment block 282, the said supporting plate may be raised or lowered to accurately position the backing wheel 245 relative to the chuck 242 on the carriage 2|8. ing wheel 245 is driven at high speed through a belt connection 263 with an electric motor 264 mounted on the supporting plate 251. By means of a thumb screw 265, the bearing 256 can be shifted laterally of the supporting plate 251 to The shaft 255 of the backaccurately adjust the backing wheel 245 relative to the longitudinal center of the carriage 2|8.

After each cut, the chuck sleeve 242 is manually turned by manipulation of 1a finger knob 266 to present a new surface of the bur head H for tooth cutting. The extent of such turning of the chuck sleeve is determined by an indexing means including a pin 261 which is mounted in the end of a spring finger 268 and which is yieldingly held in engagement with a notched wheel 269 secured to the chuck sleeve, see Figs. XII and XIII.

For the purpose of truing the backing wheel 245 from time to time as may be required, I have providedmeans as follows: Supported in spaced relation by the end and intermediate cross members 228 and 232 by the carriage 2|8, is a pair of longitudinal rods 218 and 2H which are joined at their forward ends by a tie bracket 212. The parts 228 and 212 are respectively provided with central upstanding bearings 213 and 214 for bolts 215 and 216. Respectively fulcrumed on the bolts 215 and 216 are pairs of segmental plates 211,

218 and 219, 288 carrying needle point screws 281, 282, which engage the ends of a pair of ion.- gitudinal shafts 283, 284. Set on the bars 283, 284 are holders 285, 286 respectively for diamond points 281 and 288 which are radially adjustable relative to the axis of the backing wheel 245 by means of thumb nuts 289, 298. When the is moved to the right in Fig. XII independently of the cam 226, by means of a hand lever 29! having a. fulcrum support at 292 on a pivot bracket 293 secured to the right hand end of the top 1 moved past the periphery of the backing wheel.

The lateral spacing of the diamond points may be varied through angularly adjusting the segments 211, 218 and 219, 288 about the bolts 215, 216; and after adjustment, the said segments are secured against displacement by clamp nuts 296, 291 respectively associated with the said bolts.

As shown in Fig. XV, the shafts 283 and 284 carrying the diamond point holders 285 and 286 are fitted with toothed segmental pinions 298 and 299 which respectively mesh with toothed disks 388 and 38! rotatable on a stud projection 382 of the bolt 215 at the right hand end of the carrier 2|8, see Fig. XIII. It will furthermore be noted from Fig. XV that the toothed disks 388 and 38! are formed with concentric slots for passage of a clamp screw 383 which takes into a handle 384 rockably supported by the stud projection- 382 of the bolt 215. This arrangement obviously permits circumferential adjustment of the toothed disks. 388, 38l relative to each other. Through manipulation of the handle 384 of the mechanism just described, it will be evident that the diamond point holders 285 and 286 may be simultaneously moved. The wheel truing. oper-,

diamond point 281 is moved in an arc across the beveled face on oneside of the wheel thereby truing this bevel; by further depressing the hand lever 29 l the second diamond point 288 is brought to the propertruing position at the point of backing wheel 245 is to be trued, the carriage 2 l8 tangency to the wheel and, by a second rocking movement of the handle 334, diamond point 283 trues the other beveled face of the wheel. Y

The abrasive fluid which is relied upon to actually eil'ect the tooth cutting of the bur n' is wardly from the manifold or header 303, directthe abrasive fluid in opposite streams against opposite sides of the backing wheel 243 and the bur B immediately in advance of the region where the abrading takes place, see Figs. XVI- XVIII. As a means-for impellingthe abrasive fluid under pressure, compressed air is employed in the present instance, the compressed'air; being conducted into the top of a vertical cylinder 3N (Fig. XI) containing the fluid, through a pipe 3| I. To prevent precipitation of the abrasive in the carrying fluid, a paddle 3l2 is'provided for constantly agitating it, the said paddle being attached to the lower end of a vertical shaft 3i3 which passes axially upward in the cylinder 3H) and out through a top bearing 3 to afford attachment for a pulley 3l3 adapted to be. driven by a belt 3". The supply source of compressed air may be a reservoir, such as shown at H3 in Fig. XI with a flexible delivery tube 3i! connecting with a fitting 323 interposed in the pipe 3 which enters the cylinder 313 near its upper end.

At its top outlet, the reservoir 3| 3 is equipped with a pressure gate 3 intermediate a pair of shut-off valves 322 and 323. Another shut-oi! valve 324 is provided in the air line 3|! at the fitting 323. The splash of the abrasive fluid directed against the backing wheel 233 and the'bur B undergoing cutting, as above explained, is caught by a receiver 323 which underlies the forward portion of the carriage. This receiver 323 is supported, in part by the end bracket 2| 2 of the machine, and in part by a supplemental bracket 323 secured to the top 2 of the substructure 2I3, see Figs. XI and K111. The collected fluid drains from the forward end of the receiver 323 through a depending tube 321 into a pan 328 resting on the bottom of the substructure 2M. When this pan 323 is full, the contents is discharged into a receptacle 323 (Fig. XI) whereof thebottom outlet 333 discharges into funnel 33l in a vertical terminal branch 332 of the pipe 3 which enters the top of the supply cylinder 3l0. As shown, the terminal branch 322 of the pipe 3 has interposed in it a valve 333 which is normally kept closed. However, when.

the abrasive fluid is to be introduced into the cylinder 3! from the tank 323, the valve 323 in the air line is shut off, and the valve 333 opened. The fluid thrown off under centrifugal action by the backing wheel 233 is intercepted by a guard 334 surrounding the said wheel, and thereby directed into the receiver 323 previously referred to.

In the operation of the mechanisms which I have now described, it would seem that in my process the liquid carrying minute particles of abrasive is first held upon the rotary wheels by surface tension, and then discharged tangentially therefrom by centrifugal force. This tangential discharge from the rotary wheels accomplishes propulsion of the abrasive particles in a relation substantially tangent to the steel surface to be formed and with sufficient velocity to effect abrasion thereof. v

The extreme hardness of the rotary wheel is effective to. prevent such abrasion of its surface by the liquid abrasive as would alter its contour and render ineffective its formative action upon the steel. In the grinding of the blanks as above described, the contour which is to be ground is a surface of revolution in only one direction. In the other it is a special curve or angle dependent upon the desired shape and produced by the corresponding curvature of the surface of the wheel of rotation, and between successive dressings there must be no such breaking down of the surface of the rotary wheel as will interfere with this contour, hence the necessity of the excessively hard wheel grit and the excessively hard matrix in which it is embedded, otherwise in such rapid abrading action as occurs in my process there would be alteration'of the contour formed due to too rapid destruction of the surface of the rotary wheel.

I believe that one of the important results which is obtained by the use of mypresent improvements;viz. the rapid removal of material from a body without undue heating of that body is due to the projection of a great number of emulsifled or suspended particles ofabrasive against the work surface at a high velocity; the,

forming or cutting action of such particles being proportioned to the square of the'velocity with which they are moving at the instant of the emulsifled stream of abrasive into a tapered or wedge-shaped opening between the surface of the body to be formed, (a. g. the hardened steel bur blank) and the surface, or surfaces, of the backing wheels; with the result that the particles of this stream are thus subjected to progressive acceleration as they approach their points of action, (by reason of the progressive decrease in the cross sectional area of the stream and the effect thereon of the moving backing surface or surfaces) and are projected against the material to be removed at a velocity which is comparable with, or approximate the speed of movementof the backing surface.

mation of a hardened steel surface by the employment of an emulsifled abrasive as distinguished from one which is either permanently or temporarily adherent to the wheel and I claim this as my invention. I have also spoken of this abrasive as a liquid abrasive by which I mean 'a liquid carrying a finely divided abrasive in that my claim for the accomplishment of the new and useful result which I have secured is not to be limited by theoretical considerations which subsequent more accurate knowledge may vary.

I have frequently spoken of hardened steel as the material in connection with which my new method and mechanism flnds utility but it must be understood that the same method and mech- :50 I believe it to be novel to accomplish the foriv plane is bounded by a surface of revolution,

which comprises means for rotating a hardened steel blank, means for advancing excessively hard rotating wheels in said plane of revolution into contact with the blank on opposite sides, said hard wheels consisting of a hard matrix bonding harder particles of abrasive and means for directing a separate stream of liquid abrasive into and through each restricted wedge-shaped opening formed between the hardened steel blank and each of the opposed advancing rotary wheels.

2. In mechanism for forming objects from cylindrical blanks, the combination of means for feeding cylindrical blanks in relatively abutted endless succession along their longitudinal axes into the rearward end of a chuck; means for closing the chuck upon the terminal blank; means for rotating the chuck and its contained lank and simultaneously advancing grinding means into contact with the blank for the formation therefrom of the desired object; and means for opening the chuck and simultaneously feeding out the formed object from its forward end as the succeeding blank enters the other end of the chuck.

3. Mechanism for forming articles of manufacture from cylindrical blanks, comprising a magazine arranged to embrace the opposite ends of the blanks and to deliver said blanks singly into a receiver, means operative to intermittently force a train of said blanks axially forward into a rotary chuck, means actuated to close said "buck and grip the forward blank of said train, a nd forming means cooperatively moved into contact with the rotating blank.

4. Mechanism for forming articles of manufacture from cylindrical blanks, comprising a magazine arranged to embrace the opposite ends of the blanks and to deliver said blanks singly into a receiver, a rotary blank conveyor including a chuck, arranged to convey a plurality of blanks in train formation, means arranged to successively force said blanks axially from said receiver into said rotary blank conveyor, and grinding means connected to operate in a predetermined sequence with the axial movement of the forward blank-of said train to effect the shaping of said blank into form.

5. Mechanism for forming articles of manufacture from cylindrical blanks, comprising a magazine arranged to deliver said blanks singly into a receiver, a rotary blank conveyor having an axial bore disposed in alinement with'said receiver andincluding a hollow chuck axial therewith, reciprocatory means intermittently actuated to force said blanks axially from said receiver through said conveyor and into the rearward end of said chuck and to discharge said blanks from its forward end, and grinding means connected to operate on said blank in a predetermined sequence with the intermittent axial movement of said reciprocatory means.

6. Mechanism of the .class described comprising a magazine so constructed as to deliver cylindrical blanks singly into a suitable receiver, a tubular rotary blank conveyor including a hollow chuck coaxial therewith, yielding means intermittently actuated to force said blanks axially from said receiver through said conveyor and into said chuck forwardly, means arranged to limit the movement of said blanks, and grinding means actuated in a definite sequence with the actuation of said yielding means, each forward progression of said'blanks being effective to discharge the forwardmost blank from said chuck.

7. Mechanism of the class described comprising a magazine so constructed as to contain cylindrical blanks disposed one above the other and to deliver said blanks singly into a subjacent receiver, a rotary conveyor having a bore and including a hollow chuck coaxial therewith, and.

arranged to contain a plurality of said blanks each disposed in abutted relation to the adjacent blanks, reciprocatory means intermittently actuated and tending to yieldingly force the train of relatively abutted blanks forward, a stop movably.

opposed to said blanks arranged to engage the outermost blank and arrest their forward movement until engaged by said chuck, and arranged to be retracted therefrom, and abrading mechanism actuated to engage the outermost blank and thereby effect shaping thereof, each forward progression of said blanks being effective to discharge the forwardmost blank from said chuck.

8, Mechanism of the class described comprising a magazine so constructed and arranged as 5 to contain elongated cylindrical blanks disposed substantially horizontal and to deliver said blanks by gravity into a subjacent receiver, a rotary conveyor having a bore in alinement with said receiver and including a coaxial chuck having a spring-actuated release, reciprocatory means arranged to engage and intermittently progress said blanks forwardly from said receiver through said bore and into said chuck, means actuated to intermittently close and release said chuck in sequence with the actuation of said reciprocatory means, and abrading mechanism actuated to engage the outermost blank in said chuck and thereby effect shaping thereof, each forward progression of said blanks being effective to discharge the forwardmost blank from said chuck.

9. Mechanism of the class described comprising a magazine having opposed runways for the opposite ends of cylindrical blanks and disposed to deliver said blanks by gravity into a subjacent receiver, a rotary conveyor including a hollow spindle, a chuck in the outer end of said spindle and rotated thereby, a chuck actuating chuck-rod extended throughsaid spindle and having a bore through which said blanks may be progressed in a train with their adjacent ends abutted, and delivered singly to said chuck, means arranged to intermittently move said train of blanks forward-and thereby discharge chuck the blank last held thereby, and a stop normally maintained in a withdrawn position but actuated in opposition to the movement of said blank into said chuck to limit its movement and determine its relative position in said chuck.

11. Mechanism of the class described comprising a magazine for dispensing cylindrical blanks singly into a receiver, a tubular rotary 1 to direct under pressure a separate stream of liquid abrasive focused between each coacting blank conveyor including a chuck as a unit therewith by which' said blanks are engaged one after another, yielding means intermittently actuated to force said blanks axially from said receiver through said conveyor and into said chuck to be held and rotated thereby, and

a stop normally maintained in a withdrawn position but actuated in opposition to the move-i ment of said blank into said chuck to limit its movement and determine its relative position in said chuck, said stop being actuated by a lever cooperating with a cam, and having a spring tending to maintain said lever in contact with" said cam.

12. Mechanism of the class described comprising a magazine for dispensing cylindrical blanks singly into a receiver, a tubular rotary blank conveyor including a chuck in integral relation, by which said blanks are engaged one after another, yielding means intermittently actuated to force said blanks axially from said receiver through said conveyor and into said chuck to be held and rotated thereby, and a reciprocatory cam actuated stop connected to be operated in sequence with the movement 01 said blanks to determine the position of each blank as it is thrust into said chuck.

13. Mechanism for the formation of hardened steel blanks into desired shapes, which comprises means for rotatably supporting a hardened steel blank, means for supporting a rapidly rotating excessively hard wheel, means to relatively move said blank and wheel into and out of operative contact, and means arranged surface of 'said wheel and blank.

14. Mechanism for the formation of hardened steel blanks into desired shapes, comprising means for supporting a hardened steel blank, means for rapidlyrotating' an excessively hard wheel having asubstantially V-shaped .periphery, means-arranged; reciprocate said hardened steel bla nt'o'fiand out of engagement with the; pe ery -foff'said wheel, and means arranged jt so direct under pressure from a common source of supply separate streams of liquid abrasive as to impinge upon the separate,

relatively angular surfaces of said wheel periphery at the region of its engagement with said blank.

ROBERT C. ANGELL. 

